The present invention relates to an electronic wind instrument, such as an electronic flute, and a zero point compensation method for the electronic wind instrument.
Generally, electronic wind instruments are provided with a pressure sensor for detecting a blowing (or playing) pressure applied by a user (or human player). Note-on and note-off timing control and volume control for tone formation is performed on the basis of a blowing pressure detected by the pressure sensor. Among relevant prior art literatures concerning saxophone-type or recorder-type electronic wind instruments are Japanese Patent Application Laid-open Publication Nos. HEI-9-6352 and 2002-278556.
In a saxophone-type or recorder-type electronic wind instrument, a human player (or user) performs the instrument by putting a pipe section of the instrument in their mouth to form a closed space between the pipe and the mouth and blowing breath (air) into the closed space; thus, the blowing pressure can be efficiently converted into an electrical signal via a pressure sensor provided in the closed space. Therefore, even when a temperature drift in a zero point of an output signal of the pressure sensor occurs, such a temperature drift has only a slight influence on the performance. Note that the “zero point” is an output value of the pressure sensor when the blowing pressure is zero. However, in flute-type electronic wind instruments (hereinafter referred to as “electronic flutes”) etc., which are performed by a human player blowing breath air into an open space, a breath flow detection section for detecting a flow of human player's breath is provided in the open space. Because the breath flow detection section converts the human player's breath flow into a pressure in the open space and converts the pressure sensor into an electric signal by means of a pressure sensor, a conversion efficiency in converting the player's breath flow into the final electrical signal is very poor. Thus, the breath flow detection section amplifies the output signal of the pressure with a high gain and thereby generates an electrical signal indicative of the breath flow. As a consequence, the zero point of the output signal of the breath flow detection section tends to easily move or shift due to a temperature drift. If the zero point shifts to a minus (negative) side, note-on (tone generation start) of a tone tends be difficult, while, if the zero point moves to a plus (positive) side, a tone tends to keep sounding even after the end of a player's performance of the instrument. Namely, the conventionally-known electronic wind instruments, such as an electronic flute, present the problem that a performance would be interfered with shifting, due to a temperature drift, of the zero point of the output signal of the breath flow detection section.